An alternative model for the formation of Sputnik Planitia on Pluto

Pluto with Charon in the background (Image NASA/JHUAPL/SwRI)
Pluto with Charon in the background (Image NASA/JHUAPL/SwRI)

An article published in the journal “Nature” describes a research that suggests a rapid formation of the large basin of Sputnik Planitia, a part of the heart-shaped region on the dwarf planet Pluto, in the early stages of its life. A team of researchers led by Douglas Hamilton, a professor of astronomy at the University of Maryland, concluded that its features might be the inevitable consequences of the processes that led to its evolution.

Just a couple of weeks ago two articles, also published in the journal “Nature”, described research about the heart-shaped geological formation and its consequences for the whole Pluto. New clues were also offered abou the possible presence of an underground ocean. The origin of the basin was attributed to a huge impact but now a new research provides an alternative explanation.

Douglas Hamilton’s team created computer simulations to try to understand the possible formation and evolution of Sputnik Planitia. Perhaps the basin didn’t form as a result of an impact but because of the climatic conditions on Pluto. The ice would have formed around the coldest latitudes such as the center of Sputnik Planitia. As in the previous research, one of the conclusions is that the weight would cause consequences on the dwarf planet’s motions and also on those of Charon, its main moon.

Stating that a heavy heart inevitably caused the depression sounds like a joke but it’s precisely what might have happened on Pluto. A similar phenomenon occurred in Greenland, where a basin was created by the ice when the crust it rested upon was pushed down. It’s an alternative model to the impact: each of the two might be valid but the data currently available don’t seem enough to determine whether one of the two is correct.

Douglas Hamilton was also part of the team that conducted the research that offered new clues on the possibility that there is an ocean beneath Sputnik Planitia or at least that there was one in the past. An ocean could exist even for billions of years due to the heat produced by the radioactive decay of materials inside of Pluto.

Perhaps the ocean existed in the past and at some point started freezing, forming not the common ice we know but a type with a lesser volume which requires conditions such as those on Pluto. The resulting contraction could have caused the fractures visible on the dwarf planet’s surface.

NASA’s New Horizons space probe finished sending the data collected during its July 14, 2015 flyby a few weeks ago. This means that there may be some important data about Sputnik Planitia that has still to be studied. Certainly the research about Pluto’s heart will continue.

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